Insulated panels which are intended to define spaces maintained at a low temperature, such as refrigerated compartments, generally comprise a pair of metal sheets or faces, i.e. metal linings, on a core of thermal insulation and can be fabricated by injection between the metal linings which are disposed along two broad faces of a mold, of a foam of synthetic resin or plastic material such as a polyurethane, adapted to form an isothermal or insulating core.
To permit the interfitting of such panels, edge-to-edge in a reciprocal manner, the edges of the panels are generally molded with a transverse cross section of substantially S shape defining a groove adjusting the rib of which is adapted to be interfitted or interlocked with an identical but inversely disposed profile on the opposite edge of the adjoining otherwise identical profile by mortise-and-tenon connection. In other words, the rib of one edge profile engages in the groove of the other edge profile as a tenon in a mortise, while the groove of the first edge profile receives the rib of the other edge profile as a mortise receives a tenon.
In the past, these edge profiles have been defined by strips which form the rib and groove, respectively, disposed between the metal liners before injection between them of the core of foamed synthetic resin material.
These strips, moreover, must be joined and plastered to minimize gaps between them, may have to be tapped or otherwise modified so that, during the injection of the foam, flashing will not escape between crevices between strips or otherwise.
For this purpose adhesive strips are used.
In practice, however, it has been found that all of these approaches are insufficient in that there is nevertheless some leakage and thus development of burrs or wastes which project from junctions of the strips and interfere with effective interlocking of the edges or require special removal techniques, or make it necessary to cement the junction between panels, all of which not only increases the cost, but reduces the versatility of the panel connection and creates problems with respect to the finish of the edges of the panels.
Furthermore, with the conventional edge formations, it has been found to be necessary to allow mounting of elements which are to carry units to be supported from the walls or from the ceiling by cementing them in iplace between the metal facing sheets or lining before injection of the plastic foam. This involves additional manipulative steps and creates the possibility of further defects in the product.